My setup is two 100 amp Battle Born batteries. I have the Sterling 30amp B to B charger, a Victron 2000/80/50 Multiplus inverter charger, booster. (A truly great piece of equipment) and a 10 amp 110 V cheap Li battery charger. Monitored with Victron 702.
I run refer/freezer (2 chests), Induction burner and microwave. I keep it charged most of the time, running the OB.
I am finishing a month trip with a Relion 100 amp battery the 30 amp Victorn B to B smart charger, (Also backed with a 300 watt PSW inverter to run the 10 amp charger.)
I have used from 30 to 60% of the battery (100 amp) capacity) running from 12 to 16 hours a day from the li battery for a Webasco 35 L freezer, kept at 12* in temps up to 110* in the car. I am using a cheap Chinese monitoring system--works perfectly. Conclusion that one 100 amp battery is ample for the freezer in most environments.